Apparatus and Method for Phacoemulsification

ABSTRACT

Apparatus and methods for phacoemulsification combine a phacoemulsification needle having an offset feature with a handpiece capable of producing longitudinal motion to create a hybrid phacoemulsification effect that is more efficient than conventional longitudinal handpiece-needle combinations and has been demonstrated under certain conditions to be more efficient than needles used with handpieces providing torsional motion. The phacoemulsification needle is of the type having a hollow passageway that terminates in a straight needle tip formed off-axis from the passageway, allowing the needle tip to move eccentrically when the needle is subjected to torsional or longitudinal vibratory motion. The tip may be flared or may be coextensive with the needle body. The tip may also be angled with respect to the needle body. The aspiration passageway formed through the needle body may be positioned or shaped to be off-axis from the needle body axis.

This application claims priority from U.S. provisional applications Ser.No. 61/152,622, filed 13 Feb. 2009, Ser. No. 61/154,763, filed 23 Feb.2009 and Ser. No. 61/155,145, filed 24 Feb. 2009, all of which areincorporated herein, by reference, in their entirety.

FIELD OF THE INVENTION

This disclosure relates to surgical instruments and surgical techniquesused in eye surgery and more particularly, to phacoemulsificationapparatus and methods for their use.

BACKGROUND OF THE INVENTION

A common ophthalmological surgical technique is the removal of adiseased or injured lens from the eye. Earlier techniques used for theremoval of the lens typically required a substantial incision to be madein the capsular bag in which the lens is encased. Such incisions wereoften on the order of 12 mm in length.

Later techniques focused on removing diseased lenses and insertingreplacement artificial lenses through as small an incision as possible.For example, it is now a common technique to take an artificialintraocular lens (IOL), fold it and insert the folded lens through theincision, allowing the lens to unfold when it is properly positionedwithin the capsular bag. Similarly, efforts have been made to accomplishthe removal of the diseased lens through an equally small incision.

One such removal technique is known as phacoemulsification. A typicalphacoemulsification tool includes a handpiece to which is attached ahollow needle. Electrical energy is applied to a piezoelectric crystalto vibrate the needle at ultrasonic frequencies in order to fragment thediseased lens into small enough particles to be aspirated from the eyethrough the hollow needle. Commonly, an infusion sleeve is mountedaround the needle to supply irrigating liquids to the eye in order toaid in flushing and aspirating the lens particles.

It is extremely important to properly infuse liquid during such surgery.Maintaining a sufficient amount of liquid prevents collapse of certaintissues within the eye and attendant injury or damage to delicate eyestructures. As an example, endothelial cells can easily be damagedduring such collapse and this damage is permanent because these cells donot regenerate. Some benefits of using as small incision as possibleduring such surgery are the minimization of leakage of liquid during andafter surgery to help prevent tissue collapse, faster healing time anddecreased post-operative astigmatism.

Phacoemulsification needles and tips are well represented in the priorart. Needles and tips of varying configurations are well known. Aparticular shape for a tip or needle is often dictated by the type ofhandpiece with which the needle is to be used.

U.S. Pat. No. 5,725,495 (Strukel et al) teaches and describes aphacoemulsification handpiece, sleeve and tip illustrating a widevariety of tip configurations and needle cross-sectional configurations.

U.S. Pat. No. 6,007,555 (Devine) teaches and describes an ultrasonicneedle for surgical emulsification. The needle and its tip are shown inboth circular and oval configurations.

U.S. Pat. No. 6,605,054 (Rockley) teaches and describes a multiplebypass port phacoemulsification tip having multiple aspiration ports anda single discharge port to infuse liquid into the eye.

U.S. Pat. No. 5,879,356 (Geuder) teaches and describes a surgicalinstrument for crushing crystalline eye lenses by means of ultrasoundand for removing lens debris by suction which demonstrates the use of asleeve positioned concentric to the needle and having a pair ofdischarge ports formed thereon.

U.S. Pat. No. 5,645,530 (Boukhny) teaches and describes aphacoemulsification sleeve, one variation of which has a bellows portionattached to a discharge port ring which directs an annular flow ofliquid around the needle and into the eye. The use of the bellows isintended to allow the sleeve to absorb spikes in liquid pressure duringthe operation.

Published U.S. Patent Application No. 2003/0004455 (Kadziauskas) teachesand describes a bi-manual phacoemulsification needle using separateemulsification and aspiration needles inserted into the eyesimultaneously during surgery.

Published U.S. Patent Application No. 2006/0217672 (Chon) teaches anddescribes a phacoemulsification tip that is swaged or crimped at itsdistal end. The tip is intended for use with a handpiece producingtorsional motion and the crimping forms cutting edges at the distal end.

Many phacoemulsification needles and tips are designed for use withhandpieces that vibrate the needle longitudinally at relatively lowfrequencies. In addition to longitudinal vibration, certain handpiecessold by Alcon, Inc. of Ft. Worth, Tex. claim to impart a torsionalmotion to the needle at an oscillation vibration frequency of about 100cycles/second. There are also handpieces that provide torsionaloscillation of the phacoemulsification tip at frequencies of about32,000 cycles/second.

Use of the torsional-type handpiece has called for phacoemulsificationneedle tip designs differing from those used with the longitudinal-typehandpiece. For example, needles have been designed with tips that areshaped, swaged and angled to take advantage of the needle motion createdby the handpiece.

Many surgeons favor phacoemulsification needles having the straight tipdesign commonly used with longitudinal hand pieces. The great majorityof surgeons use longitudinal hand pieces rather than torsional handpieces, often because torsional phacoemulsification equipment is moreexpensive than longitudinal equipment, and thus find themselves unableto take advantage of the enhanced phacoemulsification results claimed intorsional phaco.

Forming a needle tip in an off-axis position relative to the axis of theaspiration passageway extending through the needle body causes eccentricmotion or “wobble” during torsional phacoemulsification and improves theefficiency of phacoemulsification while retaining the straight-tipconfiguration. Surprisingly, I have also found that forming the tip insuch an off-axis position also increases the efficiency ofphacoemulsification when using a longitudinal hand piece. Preliminaryclinical examinations indicate that using an off-axis needle with alongitudinal hand piece may be more efficient than using the same needlewith a torsional hand piece providing 100% torsional action, whereefficiency is measured by the energy dissipated duringphacoemulsification. When used herein, the term “dissipated energy”refers to the amount of energy, most commonly measured in joules, usedby the hand piece during phacoemulsification. Lower dissipated energyreadings mean that less heat is being produced duringphacoemulsification which lowers the possibility of thermal damage tothe delicate eye tissues.

There are known phacoemulsification apparatus, such as the Infiniti®Vision System manufactured by Alcon Laboratories of Ft. Worth, Tex.which allow the surgeon to choose between using torsional motion,longitudinal motion, or a blend thereof in a single hand piece. A commonblended setting uses torsional motion two-thirds of the time, andlongitudinal motion one-third of the time. It is believed that the“blended” motion produces a more three-dimensional effect because of theback-and-forth motion imparted during longitudinal phacoemulsificationand the eccentric motion produced at the tip during torsional phaco.

Use of an off-axis tip with a longitudinal hand piece appears to createa hybrid type of phacoemulsification motion without using the morecomplex and expensive torsional phacoemulsification apparatus. We havealso determined that the eccentric or wobble type of motion can beimparted to a phacoemulsification needle with no flare at the tip byforming the central aspiration passageway within the needle body in anoff-axis position. It is also expected that similar results will beobtained using a straight phacoemulsification needle having anaspiration passageway that is formed with a cross sectionalconfiguration different than the cross-section configuration of theneedle body itself, and that these results will be further amplified ifthe passageway is also placed off-axis.

While the following describes a preferred embodiment or embodiments ofthe present invention, it is to be understood that such description ismade by way of example only and is not intended to limit the scope ofthe present invention. It is expected that alterations and furthermodifications, as well as other and further applications of theprinciples of the present invention will occur to others skilled in theart to which the invention relates and, while differing from theforegoing, remain within the spirit and scope of the invention as hereindescribed and claimed. Where means-plus-function clauses are used in theclaims such language is intended to cover the structures describedherein as performing the recited functions and not only structuralequivalents but equivalent structures as well. For the purposes of thepresent disclosure, two structures that perform the same function withinan environment described above may be equivalent structures.

In accordance with a preferred embodiment of the invention a method forphacoemulsification is described wherein a phacoemulsification needlehaving an off-axis configuration to produce eccentric motion is providedfor use with a phacoemulsification handpiece that produces longitudinalmotion. The needle has a straight needle tip with a flared tip formedoff-axis with respect to the hollow passage formed through the needle.

In a second embodiment the flared tip is angled with respect to theneedle body.

In another embodiment the needle tip is unflared and the aspirationpassageway is formed offset from the needle body central axis.

In another embodiment the needle tip is unflared and the aspirationpassageway has a cross-sectional shape different from that of the needlebody.

In another embodiment the needle tip is unflared and the aspirationpassageway has a cross-sectional shape different from that of the needlebody and is formed offset from the needle body central axis.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects of the present invention will be best understood byreference to the accompanying drawings in which like numbers are used toidentify like parts, and which are presented to illustrate the aspectsof the invention although not necessarily to actual scale, wherein:

FIG. 1 is a drawing showing prior art straight oval- and square-shapedtips;

FIG. 2 is a drawing showing several prior art needle cross-sectionalconfigurations;

FIG. 3 is a lateral schematic view of a phacoemulsification needleembodying the present invention;

FIG. 4 is a sectional view of the needle of FIG. 3;

FIG. 5 is an end view taken along 5-5 of FIG. 4;

FIG. 6 is a partial lateral schematic view of the needle of FIG. 5;

FIG. 7 is a lateral view of a needle tip having a circularcross-section;

FIG. 8 is a partial lateral schematic view of the needle tip of FIG. 7;

FIG. 9 is a partial lateral view of a variation of the tip shown in FIG.6;

FIG. 10 is a partial lateral view of a variation of the tip shown inFIG. 8;

FIG. 11 is a perspective view of the needle of FIG. 3;

FIG. 12 is an enlarged view of the tip of FIG. 11;

FIG. 13 is a bottom view of FIG. 12;

FIG. 14 is an illustration of the end of a prior art straight needle tipduring torsional motion;

FIG. 15 is an illustration of the end of a needle tip constructed inaccordance with the present invention and used with torsional motion;

FIG. 16 is an end view showing a needle having a triangular offset tip;

FIG. 17 is an end view of a needle having a pentagonal offset tip withthe aspiration passageway formed at an apex to adjacent sides of thepentagon;

FIG. 18 is a view of FIG. 17 showing the aspiration passagewaypositioned along one side of the pentagonal tip;

FIG. 19 is an end view of a square tip showing the aspiration passagewaypositioned at an apex of two adjacent sides of the square;

FIG. 20 is an end view of a square tip extending from a needle bodyhaving a circular outer cross-section and an aspiration passageway withan oval cross-section;

FIG. 21 is a lateral sectional view of a portion of a straight, unflaredphacoemulsification needle having a circular exterior cross-sectionshape and an internal aspiration passageway having an ovalcross-sectional shape;

FIG. 22 is an end view of the needle of FIG. 21;

FIG. 23 is a lateral sectional view of a portion of a straight, unflaredphacoemulsification needle having an oval cross-sectional shape with anaspiration passageway having a circular cross-sectional shape and offsettoward one end of the needle body;

FIG. 24 is an end view of the needle of FIG. 23;

FIG. 25 is a lateral view of a phacoemulsification needle with an angledtip formed off-axis to the needle body;

FIG. 26 is a view along 26-26 of FIG. 25;

FIG. 27 is an enlarged view of a flared phacoemulsification needle tip;

FIG. 28 is an enlarged view of FIG. 27;

FIG. 29 is a microscopic view of a portion of the outer surface of thetip of FIGS. 27 and 28 after roughening and polishing;

FIG. 30 is a microscopic view of a portion of the inner surface of thetip of FIGS. 27 and 28 after roughening and polishing;

FIG. 31 is a partial lateral view of a prior art phacoemulsificationneedle in contact with a nucleus;

FIG. 32 is a variation of FIG. 27;

FIG. 33 is a partial lateral view of a phacoemulsification needle incontact with a nucleus; and

FIG. 34 is a variation of FIG. 29.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, the numeral 10 indicates generally a prior artphacoemulsification needle tip as shown in U.S. Pat. No. 6,007,555(Devine), entitled “Ultrasonic Needle for Surgical Emulsification”,issued Dec. 28, 1999. Needle 10 is straight and terminates in anunflared mouth 12 defined by a lip 14 at the end of needle body 16, withlip 14 and needle body 16 formed as having an oval cross-sectionconfiguration.

Referring to FIG. 1, the numeral 18 indicates generally a prior artstraight, unflared phacoemulsification needle tip from U.S. Pat. No.6,007,555, having a mouth 20 defined by a lip 22 at the end of needle24. The cross-sectional configuration of needle 18 and mouth 20 is arectangle.

Referring now to FIG. 2, the numeral 26 identifies several prior artstraight phacoemulsification needles as described in U.S. Pat. No.5,725,495, with needle 28 having a circular cross-section as shown at30, needle 32 having a triangular cross-section as shown at 34 andneedle 36 having an octagonal cross-section as shown at 38. As seen at30, 34 and 38 of FIG. 2, needles 28, 32 and 36 have exterior shapes orcross-sections identical to the shape and cross-section of theaspiration passageways formed therethrough.

Both tips 10 and 18 in FIG. 1 exemplify one form of a “straight” needletip, that is, a tip that is coaxial with or centered on the hollowaspiration passageway formed through the needle body and which have noflare or enlargement at the tip. Other straight tips are known whichhave needle tips that are flared, or larger in cross-sectional area thanthe needle's aspiration passageway yet which are centered on thepassageway.

Phacoemulsification needles are sometimes referred to as “tips”. Our useof the term “tip” throughout refers to that end of the needle intendedto be inserted into the eye. The remaining portion of thephacoemulsification needle will generally be referred to as the needlebody.

Referring now to FIG. 3, the numeral 40 indicates generally aphacoemulsification needle having a flared needle tip 42 larger incross-section than and formed integrally with a distal end of a hollowneedle body 44. At a proximal end thereof, needle body 44 has a needleend 46 which terminates in a mount 48 which allows needle 40 to beattached to a phacoemulsification handpiece. Commonly, mount 48 isthreaded and screws onto a phacoemulsification handpiece. In the exampleshown, needle body 44 has a square cross-section with alongitudinally-extending central axis 50.

Referring now to FIG. 5, needle 40 is shown in lateral cross-section,illustrating the communication of aspiration passageway 6 with tip 42.

Referring now to FIG. 4, an enlarged detail of tip 42 is shown. As seenin both FIGS. 5 and 6, tip 42 has a mouth 52 defined by a lip 54 which,as shown in FIG. 3, is formed at an angle 146 to axis 50. The angleshown is one of choice: lip 54 can also be formed perpendicular to axis50 or formed in any number of other configurations correspondinggenerally to the configurations of known straight tips presently usedwith longitudinally-vibrating hand pieces.

As viewed in FIG. 5, tip 52 has a lead portion 56 and a trailing portion58, with lead portion 56 being that part of lip 54 that extendslongitudinally forward past trailing portion 58, while trailing portion58 is that part of lip 54 that extends the least distance forward. Inthe example shown in FIG. 5, trailing portion 58 is substantiallyco-linear with the outer surface 60 of needle body 44, while leadportion 56 is offset by a distance 62 from the outer surface 60 ofneedle body 44. The effect of forming lip 54 at the angle shown is toplace lead portion 56 at the farthest point from needle body axis 50.

Referring now to FIGS. 5 and 6, an aspiration passageway 64 of needlebody 44 is shown centered on axis 50. Tip mouth 52 is shown defined bylip 54 with lead point 56 and trailing point 58. In the example shown,tip 42 has its own tip axis 66 extending therethrough. As seen in FIGS.4 and 5, in this example, axes 50 and 66 do not coincide but are offsetby a distance 68. As also seen in FIG. 6, the cross-sectional area oftip 42 is larger than the cross-sectional area of needle body 44 whenviewed in a plane perpendicular to axis 50.

In a preferred example needle body 44 is 1.0 mm in exterior diameterwith a wall thickness of 0.10 mm, leaving an interior diameter of 0.80mm. Tip 42 has an exterior diameter of 1.10 mm and a wall thickness of0.10 mm. The lateral distance from the point at which tip 42 begins toenlarge outward from needle body 44 to lead point 56 is 1.80 mm, whileoffset distance 62 is 0.30 mm.

Referring now to FIGS. 7 and 8, a second example of a needle tip formedon needle 40 is shown. Needle tip 70 is square in cross-sectional shapeand is formed integrally with a hollow needle body 72. In the exampleshown, needle body 72 has a circular cross-section with alongitudinally-extending central axis 74.

Referring to FIG. 7, an enlarged detail of tip 70 is shown. As seen inboth FIGS. 7 and 8, tip 70 has a mouth defined by a lip 78 which, in theexample shown in FIG. 7, is formed at an angle 148 to axis 74. The angleshown is one of choice: lip 78 can also be formed perpendicular to axis74 or any number of other configurations corresponding generally to theconfigurations of known straight tips presently used withlongitudinally-vibrating hand pieces.

As viewed in FIG. 7, tip 70 has a lead lip portion 80 and a trailing lipportion 82, with lead portion 80 being that part of lip 78 that extendslongitudinally past trailing portion 82, while trailing portion 82 isthat part of lip 78 that extends the least distance longitudinallyforward. In the example shown in FIG. 7, trailing lip portion 82 issubstantially co-linear with the outer surface 84 of needle body 72,while lead lip portion 80 is offset by a distance 86 from the outersurface 84 of needle body 72. The effect of forming lip 78 at angle 148is to place lead lip portion 80 farthest from needle body axis 74.

Referring now to FIG. 8, the interior of needle body 72 is shown. Needlebody 72 has a central aspiration passageway 76 extending therethrough,centered on axis 74. In the example shown, tip 70 has its own centralaxis 88, which, as seen in FIGS. 7 and 8 is offset from needle body axis74 by a distance 90. As also seen in FIG. 8, the cross-sectional area oftip 70 is greater than the cross-sectional area of needle body 72 whenviewed in a plane perpendicular to axis 74.

Referring now to FIG. 9 the numeral 92 identifies a phacoemulsificationneedle constructed substantially as described with respect to FIGS. 3,4, 5 and 6. Needle 92 has a tip 94 formed with a circular cross-sectionand integral with needle body 96. Needle body 96 has a central axis 98.

Tip 92 has a square mouth 100 which, in this example, is formed at anangle 102 to axis 98. In this example, angle 102 is measured 30° in adirection opposite to that of angle 146 of mouth 52 as shown in FIG. 3.This angle is a matter of choice and other angles can be used as well.In this configuration, tip 94 has a lead point 104 and a trailing point106, corresponding in description to points 56, 58 described above. Inthis example, lead point 104 is collinear with outer surface 108 ofneedle body 96 while trailing point 106 is offset from outer surface 110by a distance 112.

Referring now to FIG. 10 the numeral 114 identifies aphacoemulsification needle constructed substantially as described withrespect to FIGS. 7 and 8. Needle 114 has a tip 116 formed with acircular cross-section and integral with needle body 118. Needle body118 has a central axis 120.

Tip 116 has a circular mouth 122 which, in this example, is formed at anangle 124 to axis 120. In this example, angle 124 is measured 30° in adirection opposite to that of angle 148 of mouth 74 as shown in FIG. 6.In this configuration, tip 114 has a lead lip portion 126 and a trailinglip portion 128, corresponding in description to lip portions 80, 82described above. In this example, lead lip portion 126 includes aportion of outer surface 130 of needle body 118 while trailing lipportion 128 is offset from outer surface 130 by a distance 132.

Referring now to FIG. 11, a perspective view of needle 40 is shown, withneedle body 42 terminating at one end at tip 42 and at the other end atthreaded mount 48. FIG. 12 is an enlarged perspective view of tip 42showing the square configuration of lip 54, leading and trailingportions 56, 58. FIG. 13 is a bottom view of tip 42 showing mouth 52,lip 54 and needle body 44.

The efficacy of having the tip axes in each of the foregoing examples benon-coincident with, or offset from, the needle body axes isdemonstrated in FIGS. 14 and 15. Using a circular tip as an example, thenumeral 134 in FIG. 11 identifies a prior art straightphacoemulsification tip having a circular cross-section defined by mouth136 integral with and extending from needle body 138. Hollow needle body138 has a central, longitudinally-extending axis 140. The geometry oftip 134 is such that axis 140 is also a central,longitudinally-extending axis for tip 134. When needle body 138 with tip134 is attached to a phacoemulsification handpiece that producestorsional motion about axis 140 the pattern of vibration is generally asshown in FIG. 14, with tip 134 exhibiting little side-to-side oreccentric motion. In other words, lip 136 tends to move in a generallyuniform motion about axis 140.

Referring now to FIG. 15, tip 70 of FIG. 8 is shown, with circular lip78 and needle body 72 having needle body axis 74 and tip axis 88. Whentip 70 is subjected to torsional or longitudinal motion, lip 78 moveseccentrically, or “wobbles”, in part because tip 70's rotation is notcentered on tip axis 88. This produces movement of lip 78 shown by paths142 and 144, creating an enhanced cutting or emulsifying effect on thetissue contacted by tip 70. Thus, a straight phacoemulsification needlewith a flared tip can be used with torsional or longitudinal motion.

The “wobble” effect can be altered by changing the offset distancebetween the tip axis and the needle body axis, and by changing thegeometry of the tip, by using different cross-sectional shapes such astriangular or polygonal.

Referring now to FIG. 16, the numeral 150 identifies aphacoemulsification tip having a triangular cross-sectionalconfiguration terminating at a lip 152 and communicating with a needleaspiration passageway 154 having an axis 156. Tip 150 has a central tipaxis 158 offset from axis 156 by an offset distance 160.

Referring now to FIG. 17, the numeral 162 identifies aphacoemulsification tip having a pentagonal cross-section terminating ata lip 164. Tip 162 communicates with a needle aspiration passageway 166proximate apex 168. Passageway 166 has a central axis 170 and tip 162has a central axis 172 offset from axis 170 by an offset distance 174.

Referring now to FIG. 18, the numeral 176 identifies aphacoemulsification tip having a pentagonal cross-sectional shapeterminating in a lip 178. A needle aspiration passageway 180 extends totip 176 proximate tip wall 182. Passageway 180 has a central axis 184while tip 176 has a central axis 186 offset from axis 184 by offsetdistance 188.

Referring now to FIG. 19, the numeral 190 identifies aphacoemulsification tip having a square cross-sectional shapeterminating in a lip 192. A needle aspiration passageway 194 is formedproximate apex 196 of tip 192. Passageway 194 has a central axis 198while tip 190 has a central axis 200 offset from axis 198 by an offsetdistance 202.

Phacoemulsification tips may also be formed on needle bodies that arenon-circular in cross-section.

Referring now to FIG. 20, the numeral 204 identifies aphacoemulsification tip having a square cross-sectional shapeterminating in a lip 206. Tip 204 extends from a needle body 208 havinga circular cross-sectional shape. Needle body 208 has an oval-shapedneedle aspiration passage 210 having a central axis 212 while tip 204has a central axis 214 offset from axis 212 by an offset distance 216.

The foregoing examples have shown tips with flared shapes, that is, tipswith cross-sectional shapes that are larger in size than the crosssectional shape of the needle body. Similar results are predicted forcertain phacoemulsification needles with no flared tip that is theterminus of the needle is the same cross-sectional shape as the needlebody.

Referring now to FIG. 21, the numeral 218 identifies a straightphacoemulsification needle having a needle body 220 through which anaspiration passageway 222 is formed. As shown in FIG. 22, passageway 222has an oval cross-sectional shape and has a central axis 224. Needlebody 220 has a central axis 226 offset from passageway axis 224 by anoffset distance 228.

Referring now to FIG. 23, a straight phacoemulsification needle 230 hasa needle body 232 formed with an oval cross-section. As shown in FIG. 24an aspiration passageway 234 is formed through needle body 232 and inthe embodiment shown has a circular cross-section. Passageway 234 has acentral axis 236 and needle body 232 has a central axis 238 offset fromaxis 236 by an offset distance 240.

While the needle bodies referred to in the foregoing examples have beenreferred to as circular in cross-section it should be understood thatdifferent cross-sectional shapes can also be used.

The foregoing examples have demonstrated round and square eccentrictips. Other tip cross-sectional shapes can also be used and the tips canbe made with various orientations. For example, tip 70 can be rotatedaround tip axis 92 to create a different orientation. It is expectedthat the wobble effect will be manifested when the axis of the tip isoffset from the axis of the needle body no matter what configuration isused.

Lips such as those shown at 50 and at 78 may also be polished to asmooth finish to add a protective feature. Phacoemulsification efficacymay also be enhanced by roughening a portion of the outer surface of thetips herein detailed.

Offsetting the tip of an angled phacoemulsification needle tip increasesefficiency as compared to a symmetrically fashioned tip.Phacoemulsification needles having flared tips that are angled withrespect to the needle body are known in the art. Heretofore, such tipshave been formed such that the bent portion of the needle body met theflared tip such that the tip was symmetrical about the needle body.

Referring now to FIG. 25 the numeral 240 identifies a portion of aphacoemulsification needle which includes a tip 242 and a needle body244. Needle body 244 has a longitudinal axis 246 and an aspirationpassageway 248 extending along its length. Tip 242 has an axis 250 thatis centered on the tip opening 252. In this example, the tip has asquare cross-section.

A bend 254 is formed on needle body 244 and, as shown in FIG. 25, tip242 is formed with a first wall portion 256 that is coextensive withbend 254 and first needle body portion 258. Tip 242 has a second wallportion 260 that is offset from bend 254 and needle body portion 262.Secondary needle body axis 248′ is shown as positioned the same distance262 from first wall portion 256 as the distance 264 axis 248 ispositioned from first needle body portion 258.

Referring now to FIG. 26, an end view of tip 242 is shown takes as aview perpendicular to line 26-26 of FIG. 5. Axes 248′ and 250 are shownto offset one from the other by a distance 266. This offset increasesthe eccentric motion exhibited by tip 242 and makes phacoemulsificationmore efficient.

The safety and efficiency of phacoemulsification tips embodying theforegoing aspects of the present invention are enhanced when the innerand outer surfaces of the phacoemulsification tip is roughened, as bysandblasting, and where the lip of the tip mouth is polished to roundthe lip and remove burrs which can damage delicate tissue in the eye,such as the posterior capsule, which may be contacted by the needle tipduring phaco.

The square tip 70 shown in FIGS. 11, 12 and 13 is exemplary of the typeof surfaces to which the roughening process is applied.

As seen in FIG. 12, tip 70 has an upper face 284, a left lateral face286, a lower face 288 and a right lateral face 290. The identifiers“left” and “right” are used here to designate those faces as seen by oneviewing FIG. 12. As can be appreciated, tip 70 has four external faces,all of which are roughened, beginning at and extending away from lip 78.

As further seen in FIG. 12, tip 70 has an inner tip surface 292extending rearward toward needle body 72 and aspiration passageway 64.It is a feature of the present invention that the inner tip surface 292is also roughened, as by sandblasting. The inner and outer surfaces oftip 70 are modified by roughening to create an uneven geometry providingnumerous projections which are engaged by the tissue being emulsified astip 70 is driven in its eccentric, or “wobble” motion.

It is another feature of the present invention to enhance the safety ofthe tips described herein by highly polishing the lip of each. Referringto FIG. 27 the numeral 294 identifies a phacoemulsification needlehaving a flared tip 296 terminating at a lip 298. In the example shown,tip 296 has a circular cross-section but the following descriptionapplies to the various tips of varying geometry described herein. Tip296 is intended to be representative of phacoemulsification tips ascustomarily manufactured. Tip 296 is shown in a magnified view.

A portion of lip 298 is seen in FIG. 28 in a more highly magnified view.The surface 300 of lip 298 is seen to meet tip 296 at substantially aright angle, forming a roughened edge 302. The same configurationcreates a roughened edge 304, formed where lip surface 300 and tip innersurface 306 meet. Tip surface 300 is also characterized by upstandingridges such as those identified by the numeral 308.

Edges 302 and 304, and ridges 308 are somewhat analogous to the“flashing” or “burrs” created when metallic workpieces are cut orsevered. Because of the relatively thin metallic material from whichphacoemulsification needles are formed, such edges and ridges arethemselves thin and sharp, certainly sharp enough to snag corneal tissuewhen a phacoemulsification needle isn inserted through a cornealincision. They are also sharp enough to damage delicate eye tissue, suchas the posterior capsule, if the needle tip is brought into contact withthe capsule during surgery.

I have determined that a process of rounding and highly polishing andsmoothing the lips of phacoemulsification needle tips of the typedescribed herein reduces the likelihood that delicate eye tissue will bedamaged during phaco, particularly if the needle is being sued with ahandpiece that produces torsional or elliptical motion.

Referring now to FIG. 29 the numeral 310 identifies the outer surface oftip 296 after a roughening procedure has been performed. As can be seen,surface 310 is “pitted” to create a much larger surface area for contactwith tissue to be phacoemulsified.

FIG. 29 also shows a portion 312 of lip 298 after polishing. Lip surface314 now meets outer surface 310 at a rounded edge 316, much smoother andsnag-free than the roughened edge 302 shown in FIG. 28.

In like fashion, a portion of inner surface 318 of tip 296 is shownafter a roughening procedure has been performed. FIG. 30 also shows aportion 320 of lip 298 after polishing. Lip surface 322 now meets innersurface 318 at a rounded edge 324, much smoother and snag-free than theroughened edge 304 shown in FIG. 28.

The elements of surface finish are described by Quality Magazine(http://www.qualitymag.com/Archives/eacd74ce57c38010VgnVCM100000f932a8c____)as form, waviness and roughness. These elements, as they are present inthe surface finish on the lips of the needles described herein, arerounded and smoothed to a degree sufficient to avoid the snagging of thetip on tissue in the eye, particularly the tissue through which thecorneal incision is made and the tissue forming the capsular bag.

While the roughening procedure has been preferably described assandblasting, other types of operations to create a controlledlyroughened surface may also be used. In like fashion, other forms ofpolishing or smoothing devices and procedures can also be used tosatisfactorily prepare the lip of each such phacoemulsification needletip.

Referring now to FIGS. 31 and 32, the numeral 270 identifies generally alens nucleus undergoing phacoemulsification using a conventionalphacoemulsification handpiece imparting only longitudinal motion tostraight phacoemulsification needle 272. As described previously, inlongitudinal phacoemulsification a needle such as 272 is alternatelymoved in forward and reverse directions at high speed.Phacoemulsification is more efficient when needle 272 is in contact withnucleus 270, particularly with traditional longitudinal phaco, because,as seen in FIG. 31, the cutting of nucleus 270 occurs when needle 272moves forward to contact nucleus 270. When the needle is drawn in thereverse direction it tends to lose contact with nucleus 272, creating agap 274.

This procedure has several readily noticeable consequences. The forwardmotion and subsequent contact of needle 272 with nucleus 270 can repulsenucleus 270 and also the fragments into which nucleus 270 is cut, makingmore difficult and time-consuming the collection of the fragmentsthrough aspiration passageway 276.

During phaco, a viscoelastic support gel is injected into the lenscapsule and the anterior and posterior chambers of the eye. One exampleof such a gel is Staarvisc® II, manufactured by Staar Surgical Companyof Monrovia, Calif. Presence of a gel in the lens capsule helps supportand protect the thin walls of the capsule. Using gel in the posteriorchamber helps protect the delicate endothelial cells which, if damaged,do not regenerate. During surgery, movement of the gel is readilynoticeable when needles such as needle 272 are vibrating. In particular,it can be seen that the gel present in the posterior chamber of the eyeis moved or agitated even though needle 272 is within the lens capsule.

As a general rule, the longer a phacoemulsification procedure lasts themore energy is expended and the more heat is produced by the ultrasoundenergy imparted to the needle. More efficient phacoemulsification isaccomplished when the lens is fragmented more quickly, the fragmentedlens particles are aspirated more quickly and cleanly and less heat isproduced. As previously described, one measure of efficiency is thetotal dissipated energy: less energy is used if the procedure is shorterand one of the ways the procedure can be shortened is to make aspirationmore effective. Another measure of efficiency is to observe suchoccurrences as the uninterrupted aspiration of particles and the“quietness” of the operating environment, meaning the relative lack ofturbulence observed in the supporting gel, both in the lens capsule andthe posterior chamber. This lack of turbulence can be quite importantwhen, for example, a surgeon is required to use a less than optimalsupport material, one that may be more susceptible to breakdown duringhigh speed vibration. One such substance is methyl cellulose which isnot as viscous or cohesive as a gel such as Staarvisc®II.

Preliminary clinical observations have confirmed that the use of anoff-axis phacoemulsification needle with a handpiece producinglongitudinal motion results in significantly more efficient phaco.Operation times have been shorter, dissipated energy levels have beenlower and the operating environment has been observed to be quieter,with much less agitation of the supporting gel and much less repulsionof the fragmented lens particles. This has resulted in markedly “clear”phacoemulsification results, meaning that the capsule is clearer ofunaspirated particles and the supporting gel has provided betterprotection to the capsule and the endothelial cells.

An ultrasonic handpiece providing longitudinal and torsional motion to aphacoemulsification needle is described in United States PatentPublication 2006/0036180 (Boukhny, et al.), entitled “UltrasonicHandpiece”. As the application states, the two modes cannot be activatedsimultaneously: the handpiece is switchable between the torsional andlongitudinal modes. A computer-controlled console allows the surgeon toselect alternating time periods for torsional and longitudinal motion,resulting in an effective “blended” motion. The characteristic of such ablended motion are altered when the time periods are altered. Forexample, a different cutting action and cutting characteristics willresult when torsional motion comprises 50 percent of the operating timethan when it comprises 75 percent.

A phacoemulsification control system described in United States PatentPublication 2008/0294087 (Steen, et al.), assigned to Advanced MedicalOptics, Inc. of Santa Ana, Calif. describes a system that imparts alongitudinal motion and lateral motion to the needle by forming theneedle with an asymmetric needle mount. Such an arrangement is believedto exhibit certain characteristics of traditional longitudinal phaco,such as the tendency for the needle to lose frontal contact with thenucleus when the needle is moved away from the nucleus, the repulsion ofnuclear particles and the tendency to transmit energy to agitate theviscoelastic gel inserted into the eye.

Combining an off-axis tip with a handpiece utilizing longitudinal motionappears to create a hybrid type of tip activity that exhibits some ofthe characteristics of this blended motion yet exhibits markedimprovements in efficiency over systems which utilize modifications tolongitudinal handpieces to achieve blended motion.

Use of the present invention can now be described. A phacoemulsificationneedle having an off-axis construction is mounted to aphacoemulsification handpiece capable of producing longitudinal motion.The geometry of the needle can include needle bodies with centered oroff-axis aspiration passageways, needle bodies with centered or off-axisaspiration passageways having different cross-sectional shapes than theneedle bodies, with such needles having straight or angled needle tipsformed off-axis to the needle body aspiration passageway, with such tipsbeing flared or unflared.

Referring now to FIGS. 33 and 34 the numeral 278 identifies aphacoemulsification needle constructed and moved in accordance with theinvention described above. FIG. 33 illustrates a straight, unflaredneedle 278 as it is being moved in the forward direction duringlongitudinal motion, showing the tip embedded in nucleus 280 with thetip mouth 282 in contact with nucleus 280. FIG. 34 illustrates needle278 in a rearward direction during longitudinal phaco. As seen herein,tip mouth 282 remains in contact with nucleus 280. It is believed thatthe hybrid motion created by combining longitudinal motion of the needlewith an off-axis needle or tip allow the aspiration suction to keep tipmouth 282 in contact with nucleus 280, greatly reducing repulsion of thenucleus and making aspiration more efficient.

With repulsion reduced the surgeon spends less time “chasing” emulsifiedlens particles with the tip mouth in order to ultimately aspirate them.Reduced agitation of the gel helps to protect the eye and preserve thefield of vision. Phacoemulsification is thus quieter, more efficient andless expensive for the surgeon.

Thus, needles embodying the present invention create a hybrid motionindependent of the type of handpiece and control console used. For thoseinstruments designed to create a torsional vibratory motion, needlesembodying the present invention create tip motion having a wider cuttingrange, covering more area. As observed, this hybrid motion appears toexhibit an energy focused more at the tip of the needle surface area,reducing wasted energy. The increase in efficiency exhibited by needlesembodying the present invention has been demonstrated by comparing thecumulative dissipated energy levels for a handpiece using both thecurrent and conventional needles to perform the same procedure. Use ofthe needles disclosed herein results in significantly reduced chatter,repulsion and thermal damage.

It is expected that the principles described herein can also be appliedto other surgical instruments as well, such as those used forliposuction and coronary plaque removal. While the present invention hasbeen described in the context of cataract removal, it should beunderstood that the principles of the present invention can be appliedto the removal of different types of tissue as well, such as tumors andthe like.

1. Apparatus for removing mammalian tissue, said apparatus comprising: ahandpiece; an elongate needle body having a proximal end and a distalend, said needle body having a central needle axis extending along itslength; an aspiration passageway formed through said needle body, saidaspiration passageway having a central passageway axis extending alongits length; means formed at said proximal end for attaching said needlebody to said handpiece, said handpiece adapted to vibrate said needle ina longitudinal direction along said central needle axis, said needlebody axis and said aspiration passageway axis being offset one from theother such that said needle body axis and said aspiration passagewayaxis do not coincide.
 2. Apparatus for removing mammalian tissue, saidapparatus comprising: a handpiece; an elongate needle body having aproximal end and a distal end, said needle body having a central needleaxis extending along its length; an aspiration passageway formed throughsaid needle body, said aspiration passageway having a central passagewayaxis extending along its length; means formed at said proximal end forattaching said needle body to said handpiece, said handpiece adapted tovibrate said needle in a longitudinal direction along said centralneedle axis; a needle tip formed at said distal end, said tip having anexterior surface terminating in a lip; said tip having a mouth definedby said lip; said tip having a central longitudinal axis; said needlebody axis and said tip axis being offset one from the other such thatsaid needle body axis and said tip axis do not coincide.
 3. Theapparatus as recited in claim 2 wherein said needle body axis and saidaspiration passageway axis substantially coincide.
 4. The apparatus asrecited in claim 2 wherein said needle body axis and said aspirationpassageway axis do not coincide.
 5. Apparatus for removing mammaliantissue, said apparatus comprising: a handpiece; an elongate needle bodyhaving an exterior surface, a proximal end and a distal end, said needlebody having a central needle axis extending along its length; anaspiration passageway formed through said needle body, said aspirationpassageway having a central passageway axis extending along its length;means formed at said proximal end for attaching said needle body to saidhandpiece, said handpiece adapted to vibrate said needle in alongitudinal direction along said central needle axis; a needle tipformed at said distal end, said tip having an exterior surfaceterminating in a lip; said tip having a mouth defined by said lip; saidtip having a central longitudinal axis; said needle body axis and saidtip axis being offset one from the other such that said needle body axisand said tip axis do not coincide; a bend formed on said needle bodyproximate said tip such that said tip is angled with respect to saidneedle body axis, at least a portion of said tip exterior surface beingnon-coextensive with that portion of said outer needle surface includedin said bend.
 6. A method for removing mammalian tissue, said methodcomprising the steps of: selecting an elongate needle having a proximalend and a distal end, a central needle axis extending along its length,an aspiration passageway formed through said needle body, saidaspiration passageway having a central passageway axis extending alongits length with said needle axis and said aspiration passageway axisoffset one from the other; mounting said proximal end of said needle toa handpiece adapted to vibrate said needle longitudinally along saidcentral needle axis; and operating said handpiece to vibrate said needlelongitudinally.
 7. A method for removing mammalian tissue, said methodcomprising the steps of: selecting an elongate needle having a needletip formed at said distal end, said tip having an exterior surfaceterminating in a lip, said tip having a mouth defined by said lip, saidtip having a central longitudinal axis, said needle body axis and saidtip axis being offset one from the other such that said needle body axisand said tip axis do not coincide, a bend formed on said needle bodyproximate said tip such that said tip is angled with respect to saidneedle body axis, at least a portion of said tip exterior surface beingnon-coextensive with that portion of said outer needle surface includedin said bend; mounting said needle to a handpiece adapted to vibratesaid needle longitudinally along said central needle axis; and operatingsaid handpiece to vibrate said needle longitudinally.
 8. A method forremoving mammalian tissue, said method comprising the steps of:selecting an elongate needle having a needle tip formed at said distalend, said tip having an exterior surface terminating in a lip, said tiphaving a mouth defined by said lip, said tip having a centrallongitudinal axis, said needle body axis and said tip axis being offsetone from the other such that said needle body axis and said tip axis donot coincide; mounting said needle to a handpiece adapted to vibratesaid needle longitudinally along said central needle axis; and operatingsaid handpiece to vibrate said needle longitudinally.